Interfacial Thermal Conductance of Suspended Graphene/Hexagonal Boron Nitride Heterojunction Devices

With the continuous scaling down of micronano electronic devices and the increasing power density, heat dissipation has become one of the key bottlenecks constraining their development. Research on the interfacial thermal conductance (ITC) of two-dimensional (2D) material heterojunctions provides ideas and approaches to address chip thermal management challenges. Constructing heterojunctions with high ITC enables efficient heat transfer, enhances the thermal management efficiency of devices, and consequently improves their overall performance and reliability. In particular, there are relatively few research reports on the ITC of suspended graphene/boron nitride heterojunction devices. In this work, we fabricated suspended graphene/Hexagonal boron nitride (hBN) (Gr/hBN) heterojunction devices. Based on Raman spectroscopy, we experimentally investigated the influence of graphene layers and temperature on the ITC of suspended Gr/hBN heterojunction devices (G). The experiment results revealed that ITC of suspended Gr/hBN heterojunction devices exhibits a decreasing trend with increasing temperature; for monolayer graphene devices, G reaches approximately 12 MW/m²K when the graphene lattice temperature is about 437 K and decreases to approximately 2.3 MW/m²K when the lattice temperature approaches 1000 K. Furthermore, G also rises as the number of graphene layers increases overall, excluding monolayer and bilayer graphene. Within the temperature range of 350 to 470 K, the maximum G are approximately 12 MW/m²K, 5.7 MW/m²K, 15.2 MW/m²K, 18.2 MW/m²K, and 26.5 MW/m²K for monolayer, bilayer, five-layer, ten-layer, and nearly fifty-layer graphene devices, respectively. Our findings provide experimental data references for designing high-performance thermal management materials and device structures.